Automatic air-feed control for rock drills



SW. A. SMITH. v AUTOMATIC AIR FEED CONTROL FOR ROCK DRILLS.

APPLICATION FILED FEB. 25, I921- Patentd May 16, 1922.

INVENT ///4' AT TO NEY UNITED STATES PATENT OFFICE.

WILLIAM SMITH, OF PHILLIPSBURG, NEW JERSEY, ASSIGNOR TO INGERSOLL- RAND COMPANY, OF JERSEY CITY, NEW JERSEY, A CORPORATION OF NEW JERSEY.

To all whom it may concern:

Be it known that I, WILLIAM A. SMIrH, a citizen of the United States, and a resident of Phillipsburg, countyof Warren, State of a New Jersey, haveinvented a certain Automatic Air-Feed Control for Rock Drills, of

which the following is, a specification,

This invention relates to fluid pressure rock drills of the hammer type, but more particularly to automatic air feed control for the feeding element which advances the machine. a The invention is especially applicable to a stope drill, although it may advantageously be used in connection with drifters and other types of rock drills for drilling substantially horizontal and down holes, whether or not the machine is provided with an independent rotation motor, rifle bar rotation or other automatic rotation. i a I i In operating a stope drill, for instance, which may betaken as an illustrative example, if a softspot is encountered the ower of the air feed should ordinarily be re need, but full rotation and hammer power should be retained,or,if possible, increased rotation should be produced, to enable the machine to operate in the most efficient manner.

These changes in the air feed control have heretofore been effected by hand and to suit the conditions of the work, and one object of the present invention is to enable the air feeding element to be automatically controlled substantially without handregulation after the drillingis started.

Anotherobject is to eii'ect such control by automatic means responsive to the resistance to the rotation and torque of the rotation motor for automatically varying the pres sure in the air feed cylinder of the air feeding element. l 1; i

In accordance with my invention, I have devised automatic means preferably directly responsive toor ailected by the torque of the rotation inotor through the agency of mechanical devices for controlling the pressure in the air feed.

Automatic regulation and control of the air feed renders the machine more sensitive to drilling conditions than can be obtained with hand controland the machine will respend automatically to the requirements more quickly than with hand control. This tends to avoid sticking, but if the steel does stick, my automatic devices have been found accompanying drawings in which- Specification of Letters Patent. Patented lay 16, 19,22, Application filed February 25, 1921. Serial No 447,757.

controlling valves to control the air feed, he may stand aside, in using a stope drill for" instance, and he is not subjected to the annoyances and discomfort of dripplng sludge and cleaning water in the case of wet drilling, which is a material. advantage for the operator.

Further obj ects of the invention will here-- inaiter appear and the invention is illustrated in one of its preferred forms in the Figure 1 is a side elevation, partly in ver-- tical section of a stope drill illustrating the invention; y y

Figure 2 is a detail diagrammatic horizontal: sectional view through the rotation motor onthe line 2+2 of Figure 11;

Figure 3 is a detail horizontal sectional view through the air feed controlling valve on the line3-3 of Figure 1 looking inthe direction of the arrows with the air feed reliei valve closed; a a t fliigure 4; is a view similar to Figure 3 with the air feed relief valve open;

Figure 5 is a detail horizontal sectional view through the air feed cylinder on the line 5-5 of Figure 1; and

Figure 6 is a detail horizontal. sectional view similar to Figure 3 showing a modification of the air feed controlling or relief a valve.

Referring to the drawings, a stope drill is illustrated in the figures having the cylinder A, and trout head B provided with the rotation sleeve C through which the drill steel xi) extends in position to receive the impact "blows oi the hammer E. An independent fluid actuated rotation motor is shown in this instance for rotating the drill steel, a gear motor being indicated having the gears F, only one ofwhich is shown in Figure 1, in

the motor casing formed by the back end porcylinder A, back end portion ormotor casing Gr, head block G, feed cylinder headG and feed cylinder H, are adapted to be held together by any suitable means as through boltsfR. v

Y The piston rod K forms a stationary nonrotatable member of the feeding element, and cylinder I-I forms a longitudinally 1nov-' able rotatable element upon which the rock drill is mounted. A guide rod S having a longitudinal groove T is longitudinally movable within the piston'rod K but held from rotation by suitable means shown as a key U lying inthe groove T and held in a sleeve V suitably connected to the piston rod. The

guide rod S is provided with a guide rod head WV held within the feed cylinder head Gr by the internally tapered bearing sleeve X. A retaining spring Y on the piston rod sleevegV is adaptedto engage the" tapered bore of the bearing sleeve X and hold the cylinder'II in retracted position when the machine is not-in use;

' The feed cylinder head-Gr is conveniently provided with a valve casing Z having a feed cylinder relief valve a movable therein, controlling the relief passage 5 opening to the atmosphere at the port 0. The valve casing is provided with the removable cap d beneath which is a coiled spring 6 which normally maintains the valve in closed position as indicated in Figure 3, clo'sing'the relief or exhaust passage from the air feed cylinder. The valve is preferably provided with the longitudinal passage 7 to prevent the building up of pressure behind the valve.

As shown, there is a clearance space 9 between the periphery of the guide rod headW and the interiorof the feed cylinder head ,G and the guide rod head is also provided with the port 72, for admitting pressure to the feed cylinder and for relieving pressure from the feed cylinder. The inner end 9' of the valve abears against a cut away portion of the guide rod head IN, and as the guide rod T and guide rod head WV are held against rotation, although capable of longitudinal movement, the guide rod head IN forms an abutment against which the spring pressed air feed relief valve a bears, and rotation of the feed cylinder H and feed cylinder head G relatively to'the guide rod T and piston rod K in the .direction of the arrows 0 in Figures 3 and 4, and tends toopen the relief valve (1 to a larger or greater extent depending upon the resistance to rotation of the drill steel.

' In the operation of the devices fluidpressure is supplied to the machine through the usual hose connection 7) controlled by the throttle Q in the head block G and the fluid supply passes through the passage 9 in the head block and the port 8 in the feed cylinder head G to the space within said head and thence through the port it to the feed cylinder. The machine will be advanced toits work until the resistance to rotation is suflicient to cause the feed cylinder H to rotate or turn in the direction opposed to rotation with suflicient force to vary the leverage and open the relief valve wand relieve the pressure in the air feed cylinder. As soon as the resistance decreases sufiiciently, the air feed relief'valve a automatically closes and full feeding is resumed. This operation continues automatically until the drilling is stopped.

In the modification shown in Figure 6, the feed cylinder head G is provided with a valve casing 25 having a valve to provided with a head 1) subjected to live air through the port w and passage a tending to hold the valve in closed position. In this case live air is substituted for the spring a and a vent 3 is provided in the valve casing t beneath the head 1). Otherwise, the operation of the valve is the same as described in connection with the other figures.

I claim: I

1. In a rock drill of the hammer type,

the combination with the drill cylinder, of means for rotating the drill steel, a feeding element for feeding the machine forward, comprising a stationary non-rotatable memher, a rotatable and longitudinally movable member connected to the drill cylinder, means for limiting the rotary movement of said longitudinally movable member, and means actuated by said rotary movement for automatically controlling said fluid pressure feeding element in accordance with the resistance to rotation. 2. In a rock drill of the hammer type, the combination with the drill cylinder, of an independent motor for rotating the drill steel, a fluid pressure feeding element for feeding the machine forward, comprising a stationary non-rotatable member, a rotatable and longitudinally movable member. connected to the drill cylinder, means for limiting the rotary movement of said longitudinally movable member, and means actuated by said rotary movement for automatically controlling said fluid pressure feeding element in accordance with the torque of the motor.

3. In a rock drill of the hammer type, the combination with the drill cylinder, of means for rotating the drill steel, a feeding element for feeding the machine forward, comprising a stationary non-rotatable memher, a rotatable and longitudinally movable member connected to the drill cylinder,

means for limiting the rotary movement of said longitudinally movable member, and a valve actuated by said rotary movement for automatically controlling said fluid pressure feeding element in accordance with the resistance to rotation.

4:. In a rock drill of the hammer type, the

combination with the drill cylinder, of an independent motor for rotating the drill steel, a fluid pressure feeding element for feeding the machine forward, comprising a stationary non-rotatable member, a rotatable and longitudinally movable member connected to the drill cylinder, means for limiting the rotary movement of said longi tudinally movable member, and a valve actuated by said rotary movement for automatically controlling said fluid pressure feeding element in accordance With the torque of the motor.

In testimony whereof I have signed this specification.

WILLIAM A. SMITH. 

